Obesity is a condition in which the natural energy reserve, stored in the fatty tissue of humans and other mammals, is increased to a point where it is associated with certain adverse health conditions. Although obesity is an individual clinical condition, it is increasingly viewed as a serious and growing public health problem. Excessive body weight has been shown to predispose to various diseases, particularly cardiovascular diseases, diabetes mellitus type 2, sleep apnea and osteoarthritis.
The main treatment for obesity is to reduce body fat by eating fewer calories and increasing exercise. A beneficial side effect of exercise is to increase muscle, tendon, and ligament strength, which helps to prevent injury from accidents and vigorous activity. Diet and exercise programs produce an average weight loss of approximately 8% of total body mass (excluding program drop-outs). Not all dieters are satisfied with these results, but a loss of as little as 5% of body mass can create large health benefits. Much more difficult than reducing body fat is keeping it off. Eighty to ninety-five percent of those who lose 10% or more of their body mass by dieting regain all that weight back within two to five years.
The body has systems that maintain its homeostasis at certain set points, including body weight. Therefore, keeping weight off generally requires making exercise and healthy eating a permanent part of a person's lifestyle. Certain nutrients or chemicals, such as phenylalanine, are natural appetite suppressants which allow resetting of the body's set point for body weight. However, diet, and exercise and/or appetite suppressants may not result in sufficient weight loss for patients with serious medical conditions.
An alternative mechanism for hunger suppression is to decrease the rate of gastric emptying without the use of ingesting chemicals. In effect, obesity can be controlled by implanting a device in the gastrointestinal tract that may regulate satiety. It should be understood that the effects of regulating satiety may vary between individuals.
Partially undigested food in the gastrointestinal track is generally referred to as chyme. A need exists for a device that is structured to inhibit the rate that chyme passes through the gastrointestinal track while allowing natural peristaltic action to occur.
Satiety receptors are generally located all along the stomach. If chyme remains in the stomach for a longer period of time than it naturally would before flowing into the small intestine, then the satiety receptors have a greater chance of being activated to signal the sensation of being satiated. Thus, a device implanted in the stomach and/or small intestine may enhance the ability of an overweight or obese patient to feel satiated so that the patient does not overeat, and in fact eat less than normal.